Add .editorconfig (#78087)

MaxDesiatov · web-flow · commit 0c7e7f345789 · 2024-12-10T13:56:00.000-08:00
This sets indentation following established precedent. The file itself is identical to the one used by the `swift-syntax` repository.
diff --git a/.editorconfig b/.editorconfig
@@ -0,0 +1,9 @@
+# editorconfig.org
+
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true
+insert_final_newline = true
